1. Field of the Invention
The present invention relates to a four lamp type headlamp for a vehicle, and to a method of constructing such a headlamp of the four lamp type.
2. Description of the Prior Art
FIG. 5 (prior art) shows two lamps of a four lamp type headlamp of a conventional type. One lighting fixture 91 called a type 1 fixture is formed for exclusive use for providing a running beam light distribution (high beam) whereas the other lighting fixture 92 called a type 2 fixture is formed to be switchable between a running beam light distribution and a pass-each-other beam light distribution (low beam). In use, during driving with the running beams in the suburbs or the like, both lighting fixtures 91 and 92 are lit to produce running beams, whereas during driving with the pass-each-other beams, one lighting fixture 91 is turned off and the other lighting fixture 92 is lit to produce a pass-each-other beam light distribution.
However, the aforementioned conventional headlamp is designed principally on the basis of driving with the running beam light distribution as will be apparent from the fact that both lighting fixtures 91 and 92 are formed to provide a running beam light distribution. This does not meet the present traffic conditions which requires driving with the pass-each-other beams under almost all conditions owing to traffic congestion caused by popularization of automobiles and the progress in road illumination. This problem should be solved.